Bones from the wrist regions (carpal bones, distal radius, distal ulna, and metacarpal bases) and the metacarpophalangeal (MCP) joints (metacarpal heads and phalangeal bases) were assessed for erosion via MRI and scored separately based on the proportion of eroded bone compared to the 'assessed bone volume' judged from all available images. Scoring ranged from 0 (no erosion) to 10 (91-100%). Results were summed, resulting in scores from 0 to 80 for the wrist region, 0 to 150 for the MCP joints, and 0 to 230 on aggregate. A negative value for change from Week 24 in bone erosion score indicated an improvement.